Revert "meta: replace os.popen with subprocess.Popen"

This reverts commit e83d8e58a6b107eea87df0ec233a1bc932b2c6e as the conversion
is not correct. Its replacing readlines() calls which generate an array with
what are effectively strings. There are split("\n") calls missing in many
cases so this needs to be reverted until it gets fixed.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/icecc.bbclass

@@ -54,7 +54,7 @@ def create_path(compilers, bb, d):
         staging += "-kernel"
 
     #check if the icecc path is set by the user
-    icecc = d.getVar('ICECC_PATH') or bb.process.run("which icecc")[0][:-1]
+    icecc   = d.getVar('ICECC_PATH') or os.popen("which icecc").read()[:-1]
 
     # Create the dir if necessary
     try:
@@ -151,9 +151,9 @@ def icc_path(bb,d):
 
 def icc_get_tool(bb, d, tool):
     if icc_is_native(bb, d):
-        return bb.process.run("which %s" % tool)[0][:-1]
+        return os.popen("which %s" % tool).read()[:-1]
     elif icc_is_kernel(bb, d):
-        return bb.process.run("which %s" % get_cross_kernel_cc(bb, d))[0][:-1]
+        return os.popen("which %s" % get_cross_kernel_cc(bb, d)).read()[:-1]
     else:
         ice_dir = d.expand('${STAGING_BINDIR_TOOLCHAIN}')
         target_sys = d.expand('${TARGET_SYS}')